The overall objective of the Nephrology Training Program at Massachusetts General Hospital is to develop individuals committed to a research career in nephrology to become independent scientists who will use novel interdisciplinary approaches to address complex biomedical problems pertaining to the kidney and the vascular system. It continues to build on its past experiences in developing productive scientists and academic nephrologists. The major components of this program include comprehensive research training under supervision of a committed mentor that incorporates a multidisciplinary approach to biomedical investigation, a dedicated and well-equipped research environment, protection from distracting responsibilities, and comprehensive programs of formal didactic instruction and enrichment activities. (A) Research Areas and Disciplines: A major strength of this training program is its multidisciplinary nature and the active collaborations among its participating faculty. This provides ample opportunities of training across disciplines, permitting novel approaches to be applied to complex biomedical problems. Training is offered in cell and molecular biology, structural biology, photobiology, stem cell biology, genetics, genomics and proteomics, innate immunity and transplantation biology, and translational research. These disciplines are applied to nine research themes that are relevant to diseases such as diabetes, hypertension, nephritis, vasculitis and polycystic kidney disease. For those trainees opting for clinical research, a rigorous program in the relevant quantitative sciences is provided. All research trainees are required to participate in an annual course in the responsible conduct of research. (B) Level of Training, Background and Numbers of Trainees. In this renewal, we request ten postdoctoral positions, offered to MDs, MD-PhDs or PhDs. Five postdoctoral fellows will begin training each year and remain in research training for at least two years supported by this award. In addition, one new pre-doctoral position is requested each year to support a minority student completing an undergraduate degree or enrolled in graduate or medical school for a 1-2 year period. (C) Training Facilities. Research training takes places in the existing laboratories of the research mentors, a multidisciplinary group of established investigators with strong collaborative interactions. The research laboratories are located at MGH, a large general hospital with~900, 000 sq. ft of space dedicated to research. In addition, trainees can also access laboratories elsewhere at Harvard and MIT. Didactic formal courses are offered at MGH as well as at Harvard Medical School, Harvard School of Public Health, Harvard University and MIT.